Multiblade rotary lawnmowers have been known and well used heretofore, although such lawnmowers have normally included rotary blades that were located in side-by-side relation that enlarged the total swath of lateral cut by the lawnmower in the operation thereof. Such rotary lawnmowers that included the side-by-side rotary blades are illustrated in the following U.S. Pat. Nos.: FAHNESTOCK, 2,188,110; LEE, 2,504,268; FLINCHBAUGH, 2,763,116; BUSH, 2,815,634; JEPSON, 2,926,478; and DOI, 4,090,346.
As illustrated in the aforesaid U.S. patents, the rotary lawnmowers described therein included rotary blades that were driven by a common drive shaft, the rotary blades being normally disposed in side-by-side lateral relation and the shafts on which the blades were mounted being spaced apart on a support for locating the rotary blades in their side-by-side lateral relationship. Although these prior known constructions did accomplish the purpose intended, that is, to provide an extended swath of lateral cut for the lawnmower during the operation thereof, the dual blades as employed in these prior known lawnmowers each performed the same function of cutting a separate area of grass or vegetation as the mower passed thereover.
In many instances when the grass to be cut has overgrown to some extent, it is necessary to fine cut after the primary pass over the lawn has been made by the mower. In such instances it is desirable to provide a simultaneous first and second cut of grass in a single pass of the lawnmower, the second cut not only fine-cutting the grass, but also mulching the grass into fines that to a great extent avoids the requirement of sweeping or collecting of the cut grass after mowing.
Prior to the instant invention, some efforts have been made to provide tandem blades in a lawnmower to effect a mulching action, one such construction being illustrated in the patent to NIEMAN, U.S. Pat. No. 2,956,386. However, even in the lawnmower illustrated in the NIEMAN patent, the mulching blades were disposed in multilevels relative to the forward cutting blade, and fine cutting of the cut grass could not be achieved.
As will be set forth hereinafter, the present invention avoids the traditional problems experienced with the usual rotary lawnmower that can effect only a single cut and that has not been provided with any effective means for fine cutting the grass after the original cut thereof or for simultaneously mulching or comminuting the cut grass.
The above-referred to patents represent the best prior art known to applicant to which the invention pertains, and reference thereto constitutes applicant's prior art statement.